Processing identity doc NFC chips: Pythonic way to handle parsing and cryptography

Kostas Jakeliūnas

At [ZealiD](https://www.zealid.com/en/), we had to implement eMRTD RFID / NFC chip reading, parsing and cryptographic verification in Python. This proved to be an interesting excursion into ASN.1 data structures and handling crypto in Python. I'll walk you through this journey of discovery and will highlight Python's strengths and gotchas here. We had to make sure we do this properly as it forms part of our qualified remote TRA process and qualified certificate issuance. Combining ability to traverse and prototype `asn1crypto` library structures and later apply `mypy` proved useful. I'll show you why!